MIMO (Multiple Input Multiple Output) system is a core technology used in 802.11n. 802.11n is a whole new wireless LAN technology following 802.11b\a\g by IEEE (Institute of Electrical and Electronic Engineers), reaching speeds of up to 600 Mbps.
It is more prevalent that modules are used in products. Moreover, there are already approaches that integrate a main antenna in a module. However, in fact, many products need to be compatible with a lot of bands, so performance requirements of the antenna are higher. In order to enhance signals, it not only needs the main antenna but also needs a sub-antenna. Ordinary 4G (Generation) antenna employs a single-board design. The main antenna and the sub-antenna are coupled to a mainboard through coaxial cables. Due to a restricted space, the two antennas interfere with each other because they are too close to each other, the performance being below standard.